The percentage of Catholics who said they were “very worried” about global warming more than doubled over the numbers this spring. And those who denied the scientific consensus that human-caused climate change is happening declined 10 percentage points for Catholics and 6 points for the US population in general.

Pollsters interviewed the same panel of just over 900 respondents before the release of the pope’s encyclical – a major document setting out Catholic doctrine – in June and also after his widely reported trip to the US in late September.

Advertisement

The authors of the survey, Edward Maibach of George Mason University in Fairfax, Virginia, and Anthony Leiserowitz of the Yale Project on Climate Change Communication, dub the shift in public opinion “the Pope Francis effect”. The effect, they say, has intensified a trend that was already in progress.

The interest of US citizens in climate change decreased sharply in 2009-2010, when people were more worried about their jobs and mortgages. But since 2010, there has been a long, slow increase in concern.

That uptick has risen more sharply since the pope issued his climate encyclical, which emphasised that climate change will affect the world’s poorest people disproportionately.

“We were expecting to find fairly small changes. The magnitude of the shift was surprising to me,” says Maibach. “In many of the specifics of the way people view climate change – for instance, seeing it as a moral issue and understanding that climate change is going to hurt people in developing countries and the world’s poor the most – we saw really large shifts.”

Trusted authority

Pope Francis is now the most trusted figure in the US on the subject of global warming, according to the survey. Six of every 10 people surveyed look to him for guidance on the subject, well ahead of politicians such as President Barack Obama, Hillary Clinton and the Republican leadership.

“A key principle of communication is that the messenger often matters more than the message itself,” says Leiserowitz, so the fact that the charismatic pope is popular among people has predisposed them to be swayed by his moral reframing of the issue.

“Climate change brings up the most fundamental questions about humanity’s place on the planet, [and] what is the proper relationship between human beings and their fellow humans,” Leiserowtitz says. “The pope has succeeded in initiating a discussion on these issues that just hasn’t been there before.”